question for Michael Manring

[mitb]

first of all, i would like to say that you are awesome. really i like your ideas, they are very original and you have a distinctive sound of your own.
maybe you have been asked many times before
but how can i get started with slapping on a fretless bass?
i have recently made my acoustic bass fretless and when it had frets, slapping sounded quite acceptable on it, now it just sounds horrible. there is no thump.
maybe its possible only on electric?
maybe i should try a diffrent tuning? ;D